This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Crews, J. K. Articles by Khalil, R. A. Search for Related Content PubMed PubMed Citation Articles by Crews, J. K. Articles by Khalil, R. A. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Hazardous Substances DB CALCIUM COMPOUNDS CALCIUM, ELEMENTAL Medline Plus Health Information High Blood Pressure

(Hypertension. 1999;34:931-936.)
© 1999 American Heart Association, Inc.

Scientific Contributions

Gender Differences in Ca²⁺ Entry Mechanisms of Vasoconstriction in Wistar-Kyoto and Spontaneously Hypertensive Rats

Janice K. Crews; Jason G. Murphy; Raouf A. Khalil

From the Department of Physiology and Biophysics and Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson.

Abstract—We investigated whether putative vascular protection against hypertension in females reflects differences in the Ca²⁺ mobilization mechanisms of vasoconstriction depending on the gender and the status of the gonads. Active stress and ⁴⁵Ca²⁺ influx were measured in aortic strips isolated from intact and gonadectomized male and female Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). In aortic strips of intact male WKY incubated in normal Krebs' solution (2.5 mmol/L Ca²⁺), both phenylephrine (10^-5 mol/L) and membrane depolarization by 96 mmol/L KCl caused significant increases in active stress and ⁴⁵Ca²⁺ influx. In intact female WKY, the phenylephrine- and KCl-induced stress and ⁴⁵Ca²⁺ influx were significantly reduced. In Ca²⁺-free (2 mmol/L EGTA) Krebs' solution, stimulation of aortic strips with phenylephrine or caffeine (25 mmol/L) to induce Ca²⁺ release from intracellular stores caused a transient increase in stress that was not significantly different between males and females. In SHR, the phenylephrine- and KCl-induced stress and ⁴⁵Ca²⁺ influx were significantly greater than those in WKY in all groups of rats. The reduction in stress and Ca²⁺ entry in intact females compared with intact males was greater in SHR than in WKY. The contractile responses and Ca²⁺ entry in castrated male and ovariectomized female WKY or SHR were not significantly different from the respective responses in intact males. The contractile responses and Ca²⁺ entry in ovariectomized female WKY or SHR with 17ß-estradiol implant were not significantly different from the respective responses in intact females. Thus, the phenylephrine- and depolarization-induced vascular reactivity and Ca²⁺ entry in vascular smooth muscle are dependent on gender and on the presence or absence of functional female gonads. Ca²⁺ release from intracellular stores is not affected by gender or gonadectomy. The gender-specific changes in vascular reactivity and Ca²⁺ entry are augmented in hypertension.

Key Words: hormones • muscle, smooth, vascular • constriction • gender • calcium

This article has been cited by other articles:

				A. K. Stennett, X. Qiao, A. E. Falone, V. V. Koledova, and R. A. Khalil Increased vascular angiotensin type 2 receptor expression and NOS-mediated mechanisms of vascular relaxation in pregnant rats Am J Physiol Heart Circ Physiol, March 1, 2009; 296(3): H745 - H755. [Abstract] [Full Text] [PDF]

				M. P. Kunert, M. R. Dwinell, I. Drenjancevic Peric, and J. H. Lombard Sex-specific differences in chromosome-dependent regulation of vascular reactivity in female consomic rat strains from a SS x BN cross Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2008; 295(2): R516 - R527. [Abstract] [Full Text] [PDF]

				D. K. Bowles, K. K. Maddali, V. K. Ganjam, L. J. Rubin, D. L. Tharp, J. R. Turk, and C. L. Heaps Endogenous testosterone increases L-type Ca2+ channel expression in porcine coronary smooth muscle Am J Physiol Heart Circ Physiol, November 1, 2004; 287(5): H2091 - H2098. [Abstract] [Full Text] [PDF]

				C. A. Kanashiro and R. A. Khalil Gender-related distinctions in protein kinase C activity in rat vascular smooth muscle Am J Physiol Cell Physiol, January 1, 2001; 280(1): C34 - C45. [Abstract] [Full Text] [PDF]